You earn $10 per hour working as a manager at a grocery store. You are required to work at the grocery store at least 8 hours pe
r week. You also teach music lessons for $15 per hour. You need to earn at least $120 per week, but you do not want to work more than 20 hours per week.
He works 6 hours at the grocery store, which is $60. Then he works 4 hours teaching music lessons, which is $60. If we add 60 and 60 we will get exactly $120.